In the gym, as in the bedroom, stamina makes all the difference. That's why the final installment of this six-part series works your abs with high repetitions to build "strength endurance"--the ability to use the strength you built in the previous workouts to add even more muscle size. This allows you to work your abs harder than ever, and your bedmate will like the results.
Do this workout 2-3 times a week. Perform the exercises as a circuit, completing one set of each exercise after another without resting. Perform 2-3 circuits, resting 2-3 minutes between each.